Opsoning

Labelling of exogenous structures by antibodies, the complement system or a combination of both. During this process, the surface of foreign bodies or pathogens (e.g. viruses or bacteria) that have entered the organism is covered by antibodies as well as by complement factors (see complement system below) due to their antigen patterns. Through this process, these pathogens are phagocytised by macrophages. The factors involved are called opsonins. The most important opsonin is the complement factor C3b, which binds to the CR1 receptor and thereby initiates phagocytosis of the allergen.